CHICAGO — Iman Shumpert and J.R. Smith were the last two Cavaliers players to leave the court Thursday night after a Cleveland celebration at United Center, a good few minutes after their mates.

“Hey, Shump, do you miss playing with Carmelo?’’ one fan bellowed as he walked off.

Yes, Knicks castaways Shumpert and J.R. Smith are into the Eastern Conference Finals, riding shotgun with LeBron James, after the Cavaliers destroyed the Bulls, 94-73, in Game 6. Shumpert scored 13 points with seven rebounds and two steals and Smith added 12 with eight rebounds.

Smith and Shumpert spoke on the bench of their good fortune when the two were replaced with 2:16 left in the blowout.

“I told Shump when I came to the sideline, I told him we’ve come a long way from being where we were at, with the guys we were with,’’ Smith said. “To be switched over like this, to be where we are now, it’s an unbelievable opportunity. We got to be make the best of it.”

On Instagram after the game, Smith ripped Knicks president Phil Jackson with a photo showing him and Shumpert in both Knicks and Cavaliers jerseys with the caption, “One man’s trash is another man’s treasure.”

With Smith suspended the first two games, Shumpert had a terrific series and became involved Thursday in the most violent — and game-turning — moment. Having a quiet night, Shumpert cut into the lane midway through the second quarter, before getting clotheslined by Bulls power forward Nikola Mirotic’s left arm.

As he tumbled to the floor, the big Mirotic took a step toward Shumpert’s fallen body. It turned into a flagrant foul and woke up the ex-Knick as Shumpert continued his dream second-round series.

“That wasn’t smart,’’ Shumpert said. “I didn’t like that at all. There was no need for it and to stand over me, that wasn’t smart. Everyone needs to have inspiration.’’

Shumpert drilled 4 of 7 shots the rest of the period, including two 3-pointers, and played maddening defense on Bulls star Jimmy Butler as the Cavaliers seized control.

In the winter, Shumpert and Smith were banged-up Knicks amid the franchise’s most dreadful season ever until it all changed one January night in Memphis when Jackson engineered a fire-sale trade with Cleveland/Oklahoma City.

Now Shumpert and Smith are good bets to get to the NBA Finals, even with Kevin Love out for the playoffs and Kyrie Irving’s knee woes worsening in Game 6 when he went down in the second quarter and didn’t return.

“With J.R. being suspended, I got more looks at the basket and had more eyes on it, but they’ve always asked me to contribute in different ways, and it doesn’t always show on the stat sheet, but I’m there,’’ said Shumpert, who averaged 13 points and 4.5 rebounds in the series.

It was poetic that the clincher happened in Shumpert’s hometown, Chicago, and against his high school rival Derrick Rose. And it was ironic that the Chicago draft combine is going on now miles away with Jackson and his staff in town. It’s also where the Knicks brass first fell in love with Shumpert four years ago and made him their first-round pick at 17 in 2011.

“Without a doubt, it was big for me. I didn’t win a lot of games in Chicago when playing for the Knicks, before these playoffs, I don’t think I’ve ever won here,’’ Shumpert said. “So it’s definitely big to close it out here. When you come from losing all those games, everything is about winning the next game. I didn’t try to make it about the Knicks trading me or anything. Business is business. And this is my team now.”

Jackson has indicated the biggest reason he traded Shumpert — beyond his free-agent status — was his belief that he was cursed by the injury bug. And Shumpert played through a strained groin in this series.

As for the Cavaliers, James already has established himself as acting head coach. If he is the acting general manager, too, he should push to re-sign Shumpert.

“He’s brought grit, toughness, the defensive mindset,’’ James said before the game. “In a sport full of a lot of egos, to be able to have teammates and guys like Shumpert who just care about team success, it means a lot to the locker room, and we’re very thankful to have him.’’